Siding Calculator

The Siding Calculator estimates how much exterior siding material you need for a wall, accounting for wall shape, openings, and cutting waste — so you can buy the right amount without guesswork. Enter your wall width, wall height, and wall type (standard, gable, or barn-style gable), then subtract any doors & windows area and set a waste allowance. You'll get the total siding needed in square feet and siding squares, plus an estimated cost if you enter a price per square foot.

ft
ft
ft

Height from roof peak to wall top (only for gable walls)

sq ft

Total area of doors and windows that won't need siding

%

Extra material for cuts, waste, and future repairs

Optional: Enter cost per square foot for budget estimate

Results

Total Siding Needed

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Wall Area

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Siding Squares

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Waste Amount

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Estimated Cost

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Frequently Asked Questions

How much siding do I need for my house?

To calculate siding needed, measure the width and height of each wall, multiply for square footage, add gable area if applicable, subtract doors and windows, then add 10% for waste. Our calculator does this automatically for each wall section.

What is a siding square and how many do I need?

A siding square covers 100 square feet. If you need 1,500 sq ft of siding, that's 15 squares. This is the standard unit contractors use for pricing and ordering siding materials.

How much waste should I add to my siding calculation?

Add 10% waste for standard installations, or up to 15% for complex designs with many cuts. This accounts for mistakes, damaged pieces, and future repairs.

Do I need to subtract doors and windows from my calculation?

Yes, subtract the total square footage of doors and windows since these areas won't need siding. A standard door is about 21 sq ft, and an average window is 12-15 sq ft.

How do I measure gable walls for siding?

For gable walls, calculate the triangular area by multiplying the wall width by the gable height (peak to eave), then divide by 2. Add this to your rectangular wall area.

What factors affect siding material costs?

Siding costs vary by material type (vinyl $2-7/sq ft, fiber cement $5-12/sq ft, wood $6-15/sq ft), quality, brand, and local market prices. Labor costs typically equal material costs.

Should I measure each side of my house separately?

Yes, measure and calculate each wall separately, then add the totals together. Different sides may have different numbers of windows and doors to subtract.

How accurate are siding calculator estimates?

Siding calculators provide good estimates for planning and budgeting, but always have a professional measure for final material orders. Complex architectural features may require additional material.